Elevating scraper



Dec. 20, 1966 c. M. JOHNSON ELEVAT I NG S CRAPER :j Sheetshoet l Filed Sept. i7, 1963 KWB Dec. 20, 1966 c. M. JOHNSON 3,292,278

ELEVATING SCRAPER Filed Sept. L7, 1965 I5 Sheets-Sheet I3 INVENTOR ATTGRNEYS Dec. 20, 1966 c. M. JOHNSON 3,292,278

ELEVATI NG SCRAPER Filed Sept. 17. 1965 Y Sheets-Sheet 3 //Z /f /z I NVE NTOR Jeff/Q55 /Kf/f//vm ATTORNEYS United States Patent 3,292,278 ELEVATING SCRAPER Charles M. Johnson, Lubbock, Tex., assgnor to Johnson Manufacturing Company, Lubbock, Tex., a corporation of Texas Filed Sept. 17, 1963, Ser. No. 309,474 14 Claims. (Cl. 37-8) This invention relates to earth scraping and moving machines yand in particular to equipment of the type having an endless elevating conveyor for assisting in loading dirt into the equipment.

In very recent years it has become a common practice to provide earth Scrapers of the type which carry a downwardly extending scraper blade at their front end with a power-driven endless conveyor mounted between the side walls of the scraper above and rearwardly of the scraper blade. Conventionally the endless conveyor is inclined upwardly and rearwardly 'and is pivotally mounted near its upper end for rotation in a vertical plane about a horizontal `axis which is transverse to the scraper. In operation the lower end of the conveyor rides on top of the loosened earth which has passed over the scraper blade and movement of llights or slats attached to the endless chains of the conveyor urge the earth rearwardly into the bowl of the scraper. Further details of the operation and construction of earth Scrapers equipped with elevating conveyors may be found in Patent No. 2,984,022, issued May 16, 1961.

In the usual construction the conveyor chains are looped over drive sprockets at their upper ends and over freely rotatable rollers at their lower ends, the sprockets and rollers being mounted at opposite ends of a rigid conveyor frame. The sprockets may be rotatably driven by a mechanical drive linkage from a power take-olf on the towing vehicle or by an electric or hydraulic motor carried on the scraper.

Normally, in relatively small Scrapers, -no particular problems are associated with constructing and maintaining the elevating conveyors. However, the size of scrapers being manufactured has been continually increasing and the corresponding increase in the size and weight of the conveyor has introduced mechanical problems which were heretofore not experienced. In particular it has been found that the top sprockets and the bottom rollers are subject to considerable wear and occasional breakage. Replacement of these parts involves, of course, the expense of the parts but more important is the time, labor and expensive equipment which has formerly been required to effect the replacement. Heretofore each of the top sprockets and bottom rollers has been of conventional unitary construction, tand in order to replace one of these parts it has been necessary to remove the conveyor from the scraper and disassemble it. Since the newer conveyors weigh at least several thousand pounds, large hoisting equipment was required.l Frequently hoisting equipment of this type is not readily available, particularly at remote work locations and consequently considerable time and money were lost in making repairs of this kind.

Accordingly, it is a primary object of the present invention to provide an earth scraping machine having an elevating conveyor in which improved mounting and drive elements for the conveyor reduce wear and breakage of parts, particularly the drive sprockets and rollers, and permit easy replacement of these parts with ordinary tools.

It is another object of the invention to provide an earth scraping machine of the above type in which each of the drive sprockets and the rollers of the conveyor is of split construction whereby they maybe easily replaced Mlee Without removal of the conveyor from the machine and without disassembly of the conveyor.

It is further an object to provide an earth scraping machine of the general type described in which the mounting members for the conveyor include 1an improved Ibiasing and guide arrangement for urging the lower end of the conveyor into engagement with incoming dirt and for absorbing shock to thereby reduce wear.

The invention will be further understood from the following detailed description in conjunction with the drawings in which:

FIGURE l is a side elevational view of an earth scraping machine embodying the principles of the present invention;

FIGURE 2 is a front elevational view of the top portion of the conveyor, partly broken away, looking in the direction of the arrows 2 2 in FIGURE 1;

FIGURE 3 is a sectional view taken on the line 3 3 of FIGURE 2;

FIGURE 4 is a top plan view, partly broken away, of the lower portion of the conveyor of FIGURE l;

FIGURE 5 is a sectional view taken on the line 5 5 of FIGURE 4;

FIGURE 6 is a schematic side elevational View, on an enlarged scale of the conveyor of FIGURE l;

FIGURE 7 is a sectional view taken on the line 7 7 Of FIGURE 6;

FIGURE 8 -is a sectional view taken on the line 8 8 of FIGURE 6;

FIGURE 9 is a sectional view taken on the line 9 9 of FIGURE 8;

FIGURES l0 and 1l are fragmentary views of a modilied form of an arrangement for supporting the upper end of the conveyor;

FIGURES 12 and 13 are fragmentary views of another modied form of an arrangement for supporting the upper end of the conveyor;

FIGURE 14 is a schematic elevational view of yet another modified form of conveyor support; and

FIGURE 15 is a side elevational view of a modified lower guide element for a conveyor.

Referring to FIGURE l there is shown an open-top, open-front earth scraping machine 10 having side walls 12 supported and reinforced by external frame members 14 and a downwardly and forwardly extending earth scraping blade 16 extending transversely between the side walls 12. The bottom of the scraper is delined by a longitudinally movable bottom wall section 18 located rearwardly of the blade 16 and a xed bottom wall section (not shown) rearwardly of and slightly above the movable section 18. The movable section 18 is suspended from a pair of horizontal side rails 22 by means of rollers 24 which are rotatably mounted in brackets extending upwardly from the lower section 18. The forward end of the section 18 carries laterally extending pins 26 which reside in notches 28 in side plates 30 when the section is in the full forward position. The rear end of the scraper 10 is supported by a pair of laterally spaced, ground engaging wheels 32 which are mounted on additional frame members 34 by means of a suitable axle and bearings.

The scraper 10 is connected to a tractor 36 having ground engaging wheels 37 by means of a Y-shaped beam structure having a pair of laterally spaced legs 38 which straddle the forward part of the machine and which are pivoted to the outside of the side walls 12 as by bolts 39. Forwardly of the machine the legs 38 converge to form a gooseneck structure 40 which is connected to the tractor 36 by means of a conventional coupling 42 which permits pivotal motion between the tractor 36 and the scraper 10. A hydraulic cylinder 44 for raising and lowable manner.

ering the front of the scraper is pivoted at one end to the forward end of the scraper 10 and to the gooseneck 40 at 46.

An endless elevating conveyor 48 extending upwardly and rearwardly is pivotally mounted between the side walls at the front of the scraper 10 for rotation in a ver,- tical plane. The conveyor includes, as conventional elements, a pair of laterally spaced rigid frame members 50 i and a pair of endless chains 52 .which carry a plurality of transverse, generally L-shaped scraping flights 54. In the embodiment illustrated the chains 52 and flights 54 are driven by a hydraulic motor 56 attached thereto and receiving its pressurized uid through flexible lines 58 from a source 60 on the tractor 36. It will be understood, however, that the conveyor 48 may be driven in any suit- The movable bottom wall 18 is also hydraulically operated by a suitable mechanism (not shown) carried at the rear of the scraper 10v and provided with a hydraulic fluid line 62. Further details of a hydraulically driven elevating conveyor and a movable bottom wall may be found in application Serial Nos. 255,591, filed February 1, 1963, and 279,987, filed May 13, 1963, respectively. f

According to one feature of the invention and referring to FIGURES 2-5 the upper end of the conveyor is mounted so that the drive parts may be easily disassembled in the event that replacement of any of the parts is required. In particular the conventional unitary drive sprockets are replaced with split drive sprockets 64 which as seen in FIGURE 3 consist of two arcuate halves 66 and 68 from the outer edge of which extend chain engaging teeth 70. The halves 66 and 68 of each sprocket are secured to a shaft 72 which extends transversely between the conveyor frame members 50. As seen in FIGURE 2, the two halves 66, 68 of the respective split sprocket 64 are held between two transversely spaced annular backing plates 76, 78 by a plurality of bolts 80 which pass through circumferentially spaced holes in the plates and in the sprocket halves. One of the backing plates 76, 78 is secured to the shaft 72 as by welding and the other is loosely mounted on the shaft 72 so that it can be drawn up tightly against the sprocket halves 66, 68.

The shaft 72 is journalled at one end in a bearing 74 carried by one leg of a longitudinally adjustable extension 75 on the frame members 50. The other end of the shaft 72 is connected to the hydraulic motor 56 through a gear reduction unit 82 carried by one of the frame members 50.

The split sprocket halves 66, 68 permit either of the sprockets to be easily removed from the shaft 72. The conveyor is rotated to a position in which one of the sprocket halves is substantially out of contact with the chain and then the bolts associated with that half are removed.y The sprocket half 68 may. then be slipped outwardly from the shaft 72 in a radial direction and replaced with a new part without removing the shaft 72, bearings 74 or gear reduction unit 82 from the frame members 50. If the other sprocket half is to be replaced the conveyor is rotated again to substantially disengage the other half from the chain and the process is repeated. Thus it is possible to replace these parts in the field with ordinary hand tools thereby avoiding waste of time in obtaining heavy maintenance equipment or in moving the scraper 10 to a shop.

In a similar manner, as seen in FIGURES 4 and 5, the conventional chain supporting rollers at the bottom of the conveyor 48 are replaced with split rollers 84 each consisting of two arcuate halves 8 6, 88 over which the chains 52 are looped. The roller halves 86, 88 are secured to a shaft 90 extending parallel to the sprocket shaft 72 and journalled at its ends in bearings 92 carried by longitudinally adjustable extensions 93 (FIGURE 6) on the frame members 50. Each pair of halves 86, 88, is carried between a pair of annular backing plates 94, 96 one of which is secured as by welding, to the shaft 90. A plurality of circumferentially spaced bolts 98 extend through 4 the plates 94, 96 and the halves 86, 88. As with the split sprockets 64 the split rollers 84 may be readily removed from the frame members '50 with ordinary hand tools.

In the preferred construction of the conveyor 48 wearl on the sprockets 64 and rollers 84 is reduced by providing idler wheels which take some of the weight of the chains,

52 and flights 54. Referring to FIGURES 1, 6 and 7 there is shown a toothed idler wheel 98 engagingthe inner periphery of each chain 52 intermediate the ends.V

of the conveyor 48. Each of the idlers 98 is rotatably mounted on one end of an arm 100 by means of a shaft 102. Each arm 100 is adjustably mounted on a bracket plate 104 for adjustment toward and away from its chain 52 by Imeans of a 4bolt 106 which passes through the arm` and through a curved slot 108 in the bracket plate 104.`

The bracket plates 104 are secured to the frarne members as by welding. Each chain 52 is provided with two longitudinally spaced idlers 98, one of which is shown in FIGURE 1 and the other being shown in FIGURE-6.

According to another feature of the invention the conveyor 48 is mounted in an improved manner which urges and guides the lower end of the conveyor 48into er1;

gagement with incoming dirt and which also absorbs shock produced by hard clods of earth or large stones` entering the scraper 10. Referring to FIGURE 6 it will be seen` that the conveyor is provided with a transverse support shaft 110 which is fixed to the frame members 50 near their upper ends in any suitable manner and which ex-` tend-s laterally beyond the sides thereof. Each end of this shaft 110 is pivoted to the upper end of a downwardly and rearwardly extending link 112 which in turn is pivoted at its lower end to the inside of the respective scraper, side wall 12 as by a bolt 114. Rotational movement of each link 112 in a vertical plane is limited by a pair of spaced` URES 6, 8 and 9 a set 126 of leaf springs is fixed to the` conveyor support shaft and extends downwardly into engagement with the stop member 116 so as to yieldingly resist clockwise rotation of the shaft 110 as viewed in FIGURE 6.

The set 126 of springs includes a plurality of overlying spring strips 128 of different lengths held together near their upper ends by a pair of clamping plates 130, t

132 and a pair of bolts 134 which pass through the plates 130 and the spring strips 128. The upper clamping plate 132 is integral with a hanger sleeve 136 which surrounds the conveyor support shaft 110 and which is secured thereto. A pin 138 extending upwardly from the clamping plate 130 passes through the sleeve 136 and through the conveyor support -shaft 110 and is provided at its upper end with a nut 140. The shaft 110 is also keyed to the sleeve by a key 142. As best seen in FIGURES 6 and 8 the free end of the spring set 126 rides on the upper rear surface of the forward stop member 116.

In conjunction with the rspring biased upper support arrangement the conveyor 48 is provided with a lower guide system illustrated in FIGURE 6. As seen therein a transverse shaft 144 is fixed to the conveyor frame members 50 slightly above the bottom chain rollers 84 and extends laterally beyond the frame members 50. A roller 146 is rotatably mounted at each end of the shaft 144 for engagement with a roller guide 148 which is se. cured to the inside of the respective side wall 12 with bolts 150. The guides 148 are provided with a plurality of bolt holes 152 so that the angle and position of the guides may be changed,

Each guide 148 is a plate having a generally hookshaped rear edge which faces upwardly and rearwardly. The respective roller 146 rides on this edge in a variety of positions depending on the load of dirt entering the scraper 10. When no dirt is passing over the scraper blade 16 the rollers 146 ride on a portion 154 of the rear edge of their guides which is inclined slightly upwardly. As dirt begins to build up on the blade 16, the lower end of the conveyor 48 rides up on the dirt and at the same time the spring set 126 moves the entire conveyor slightly downwardly. In this position the guide rollers 146 reside at a curved junction between the rearwardly inclined edge portion 154 with a forwardly inclined edge portion 156. As the incoming load of dirt further increases the rollers 146 ride upwardly and forwardly along the edge portions 156 until further movement is restrained by downwardly and Irearwardly facing arcuate portions 158.

FIGURES and l1 illustrate a modilied form of a spring biased support for the upper end of the conveyor 48. As shown therein an upwardly and forwardly extending link 160, corresponding generally to the conveyor support link 112 in FIGURES 1, 6, 8 and 9, is pivoted at its lower end to a scrapper side wall 162 by a pin 164 and to a transverse conveyor support shaft 166 corresponding to the shaft 110 in the aforesaid figures. A spiral torsion spring 168 surrounds the shaft 166 and is secured at its inner end to the shaft 166 by a pin 170 and at its outer end 172 to the link 160 by projecting into a hole in the .link 160. The torsion spring 168 thereby yieldingly resists clockwise rotation of the shaft 166and consequently operates in a manner equivalent to the lea-f spring set 126.

Where hard clods of earth and large stones are expected to be encountered by the conveyor it is preferred to incorporate a shock absorber 174 bet-Ween the shaft 166 and the side wall 162. As seen lin FIGURES 10 and 11 the shock absorber 174, which may .be of a conventional automotive type, is pivoted at its lower end to the side wall 162 by a pin 176 at a location forwardly of the conveyor support arm 160. The upper end of the shock absorber 174 is disposed slightly rearwardly of its lower end `and -is pivoted on an extension 178 of the link 160 by means of a pin 180. The absorber 174 becomes compressed and absorbs energy when the lower forward end of the conveyor drops under the action of gravity and the spring 168.

In another modified form of conveyor support, illustrated in FIGURES 12 and 13, la transverse conveyor support shaft 182 is pivoted to the upper end of an upwardly and forwardly extending link 184. Each end of the shaft 182 resides in a sleeve 186 which -is secured to one of the links 184. Rotation of the shaft 182 within the sleeves 186 is limited by a stop member 188 protruding from the shaft 182 through a relatively wide slot -190 in the sleeve 186. In this modification a spiral torsion spring 192 surrounds -a pin 194 which pivots the link 184 to a scraper side Wall 196. The inner end of the spring 192 is attached to the pivot pin 194 by a pin 198 and the outer end 200 extends linto a hole in the link 184.

In yet another form of conveyor support, illustrated schematically in FIGURE 14, a transverse conveyor support rod 202 is pivoted 4at each end to the upper end of a support link 204 -which is .biased forwardly and downwardly by means of a spiral tension spring 206. One end of the spring 206 -is hooked through a hole 208 in an upper extension 210 of the link 204. The other end is hooked through Ia hole in a bracket 212 which is secured to a scraper side wall 214 at a location forwardly of the link 204.

The lower end of the link 204 is pivoted to the side wall 214 by a pin 216 to which is also pivoted one end of a lower support link 218. The opposite end of the lower support link 218 is pivoted about a lower transverse support shaft 220 which, like the `shaft 202 is fixed to the conveyor frame illustrated by the dashed line 222. A stop 224 is secured to the side wall 214 for limiting downward movement of the link 218. Intermediate the ends of the link 218 is a spiral compression spring 226 surrounding a lower portion 227 of the link 21S and having its upper end 228 secured thereto. The lower end 239 of the spring 226 is secured to a sleeve member 232 which surrounds the spring 226 and in which the link porti-on 227 is longitudinally slidable. The upper end of the sleeve mem-ber 232 threadedly engages an extension 234 which forms the upper portion of the link 218.

It will be noted that no stop members for the upper conveyor support links are shovm in FIGURES 10-13. In these modifications a pair of guide members similar to the roller guides 148 are employed to serve as stop members as 'Well as guide members. As seen in FIG- URE 15 each of these guide members 236 provides guide surfaces 238, 240 and 242 which are the same as the guide surfaces 154, 156 and 158 respectively, of FIG- URE 6. In addition the member 236 is provided with an extension 244 which closes the concave face of the hookshaped edge so as t-o positively guide a roller 246 on the lower end of -a conveyor. As shown the extension 244 may be integral with the hook-shaped portion or it may be a separate piece held in place with bolts.

In operation, the scraper 10 is towed forwardly (to the left as viewed in FIGURE 1) by th'e tractor 36. When it is desired to scrape dirt into the scraper 10, the tractor operator `starts the conveyor drivemotor 56 and extends the hydraulic cylinder 44 to lower the forward end of the scraper 10 thereby engaging the scraper blade 16 with the surface of the ground.

Atthis time the conveyor 48 is in the position illustrated schematically in FIGURE 6, that is, the leaf spring 126 or theother forms of biasing spring shown in FIG- URES 10-14 produce a torque on the conveyor which tends to rotate it counterclockwise about its upper support shaft 110. The rollers 146 at the lower end of the conveyor are therefore urged into :a position engaging the downwardly and forwardly extending guide surface 154 (or 238 in FIGURE 15).

When di-rt loosenedby the scraper blade 16 begins to pass over the blade 16 the conveyor flights 54 engage the dirt and effect upward and rearward forces which tend to pivot the conveyor clockwise around its upper support shaft 110. However, the'spring 126 tends to resist this movement so that `as the llower end of the conveyor pivots clockwise to allow the dirt to pass thereunder, the spring 126 in cooperation with the guide 148 urges the entire conveyor 48 downwardly and forwardly. Thus at moderate incoming loads the guide roller 146 will assume a position at the junction of the guide surface 154 with the upwardly and forwardly extending surface 156. It will .be :appreciated that this movement of the conveyor not onlyma-intains the flights 54 in contact with the incoming dirt but it :also extend-s the conveyor slightly tow-ard the incoming dirt so as to keep the flights 54 in contact therewith for as long a time as possible.

When heavy loads are encountered as for example in moving very heavy tight soil or large rocks the -lower end of the conveyor must, `of course, move upwardly to permit the load to pass into the scraper. This movement is a generally clockwise rotation of the conveyor about the shaft and the pin 114 produced by the force of the incoming load. The upwardly and rearwardly extending guide surface 156 of the guide element 148 prevents forward movement of the entire conveyor as was the case of a moderate increase in load and thereby tends to lessen the engagement between conveyor 'and load. This latter movement therefore reduces the shock on the conveyor when heavy loads are encountered. The lower end of the conveyor is prevented from riding up too high on an incoming load by engagement of the support link 112 with the rear stop member 118 or, in the FIGURE 15 embodiment, by engagement of the roller 246 with the guide extension 244.

Thus it will be appreciated that the present invention provides :an elevating conveyor for an earth scraper in which the drive sprockets and chain supporting rollers 'are easily replaced if they become damaged or broken and in which the conveyor mounting is designed to give high eiciency while reducing unnecessary wear and tear on its moving parts. While several construct-ions have been described, m-odications will occur to those skilled in the art and it is not intended that the described details be limiting except as they appear in the appended claims.

What is claimed is:

1. An earth scraping machine comprising: a mobile, open-front, open-top earth carrying container having laterally spaced side walls; a downwardly and forwardly extending earth scraping blade carried `at the front of said container between said side walls; :an elongated endless conveyor between said side walls at a position above said scraping blade, said conveyor extending upwardly and rearwardly and having an elongated rigid frame means; means for pivotally mounting said conveyor for movement in a vertical plane, said means including a forwardly :and upwardly extending conveyor support link pivoted about a transverse axis at its upper end to said frame means intermediate the ends of said frame means and -about another transverse axis at its lower end to one of said side walls; biasing means yieldably urging the lower forward end of said conveyor downwardly; and means for guiding the lower end of said conveyor from a first position above the level of said scraping .blade assumed when no dirt is passing over said blade to an intermediate positi-on forwardly and downwardly of said first position assumed when a moderate amount of dirt is passing over said blade and then to a iinal position forwardly and upwardly of said intermediate position, said guide means including a rigid guide element disposed along the inside of one of said side walls adjacent the lower portion of said conveyor and having a guide surface engaged by said conveyor, said guide element being supported by said one side wall; and means for preventing upward movement of the lower end of said conveyor beyond a predetermined point.

2. An earth scraping machine as in claim 1 in which said biasing means includes a leaf spring xed at its upper end to said frame means near the upper end thereof and extending downwardly and rearwardly; and fixed means secured to a side wall engaging the forward surface of said spring whereby said spring exerts torque on said conveyor in a direction to urge the lower end thereof in a downward direction.

3. An earth scraping machine las in claim 1 in which said conveyor supporting link is pivoted on a lateral extension on said frame and on transversely extending pin means associated with said one side wall and wherein said biasing means includes .a spinal torsion spring surrounding said extension on said frame, the end ofl said spring nearest said frame being secured to said extension and the other end of said spring bein-g secured to said conveyor lsupport link.

4. An Vearth scnaping machine as in claim 1 in which said biasing means includes a tension spring secured at one end to said conveyor support link near the upper end thereof and to said one side wall at a location forwardly of said link.

5. An earth scraping machine as in claim 4 in which said .biasing means further includes a second conveyor support link pivoted at one end at the lower pivot point of said first-named link, and extending downwardly and forwardly, the lower end of said second link being pivoted to said conveyor frame near the lower end thereof for rotation about an axis transverse to said conveyor, said second link including two end-to-end portions joined by spring means.

6. An earth scraping machine as in claim 1 in which said rigid guide element is a generally hook-shaped plate` with the concave edge of said plate facing generally rear-` wardly and forming said guide surface.

9. An earth scraping machine as in claim 8 wherein` said guide surface includes a downwardly and forwardly extending portion merging at its `lower end with an up` wardly and forwardly extending portion whichmerges with a concave portion facing rearwardly and downwardly. 10. An earth scraping machine as in claim 8 wherein the upper end of said hook-shaped plate is provided with a downward extension which closes ol at least a portion of the open face of the hook thereby forming said means for preventing upward movement of the lower end Aof said conveyor beyond a predetermined point.

11. In an earth scraping machine of the kind including a mobile, open-front, open-top earth carrying container having laterally spaced side walls, ascraper blade carried at the front of said container, an elongated endless con-` veyor having a rigid frame extending upwardly and rear-` wardly between said side walls, and means for pivotally mounting said conveyor for movement in a vertical plane including forwardly and upwardly extending conveyor support links pivoted at their upper ends to said frame intermediate the ends of said frame for movement about a transverse axis and pivoted at their lower ends to the.

sides of said container for movement about another transverse axis, the improvement comprising: biasing means operatively associated with said conveyor for yieldably` urging the lower forward end` of said conveyor downwardly and for allowing said lower end to move upwardly against the action of said biasing means so as to rise up over an obstruction passing over said scraping blade; and shock absorber means operatively associated withsaid` conveyor and cooperating therewith to absorb energy.V

when said lower forward `end of said conveyor drops under the action of gravity and said biasing means, said shock absorber means including a self-contained shock absorber mechanism having two parts which are movable relative to each other in two directions and further including mounting means associated with one of said parts and carried by said container for restraining movement of said one part relative to said container, the otherof said parts being operatively connected to move relativeto 'said first part upon downward movement of said lower end of said conveyor.

12. An earth scraping machine as in claim `11 wherein said relatively movable parts of said shock absorber mech-1 anism define opposite ends of said mechanism and are` movable longitudinally of each other in an energy-absorbt ing direction and in a non-energy-absorbing direction, one i of said ends being carried by said mounting means and the other of said ends being connected to move longitudinally of said one end -in said shock absorbing direction upon downward movement of said lower end of said conveyor.

13. An earth scraping machine as in claim 12 wherein said shock absorber mechanism is pivotally connected between a side wall of said container and an extension on the upper end of one of said conveyor support links.

14. In an earth scraping machine of the kind including a mobile, open-front, open-top earth carrying container having laterally spaced side walls, a scraper blade carried.` at the front of said container, an elongated endless coni veyor having a rigid frame extending upwardly and rearwardly between said side walls, and means for pivotally i 94 mounting said conveyor for movement in a vertical plane including forwardly and upwardly extending conveyor support links pivoted at their upper ends to said frame intermediate the ends of said frame for movement about a transverse axis and pivoted at their lower ends to the sides of said container for movement about another transverse axis, the improvement comprising: means for continuously urging the lower surface of said conveyor into maximum engagement with dirt passing over said scraper blade and for maintaining said engagement during a dirtscraping operation, said means including biasing means operatively associated with said conveyor `for yieldably urging the lower forward end of said conveyor downwardly and further including guide means fixed to said container near said lower end of said conveyor, said guide means having an elongated guide surface, said conveyor having a xed guide element which is maintained in continuous engagement with said elongated guide surface during normal scraping operations by the downward force exerted on said conveyor by said biasing means, said guide element, guide surface and biasing means coacting with the force created by dirt passingover said scraping 10 to move said lower end of said conveyor a short distance downwardly and simultaneously forwardly at moderate incoming dirt loads and to move said lower end of said conveyor further forwardly and simultaneously upwardly at higher incoming dirt l-oads.

References Cited by the Examiner UNITED STATES PATENTS 2,984,022 5/ 1961 Johnson 37-8 3,048,934 8/1962 Hancock 37-8 3,083,585 4/1963 Dawe et al 74-243 3,090,139 5/1963 Hancock 37--8 3,106,101 10/ 1963 Harriman 74-243 3,191,322 6/1965 Johnson et al. 37-8 3,210,868 10/ 1965 Liess 37-8 FOREIGN PATENTS 890,598 3/ 1962 Great Britain.

ABRAHAM G. STONE, Primary Examiner.

F. B. HENRY, R. L. HOLLISTER, Assistant Examiners. 

1. AN EARTH SCRAPING MACHINE COMPRISING: A MOBILE, OPEN-FRONT, OPEN-TOP EARTH CARRYING CONTAINER HAVING LATERALLY SPACED SIDE WALLS; A DOWNWARDLY AND FORWARDLY EXTENDING EARTH SCRAPING BLADE CARRIED AT THE FRONT OF SID CONTAINER BETWEEN SAID SIDE WALLS; AN ELONGATED ENDLESS CONVEYOR BETWEEN SAID SIDE WALLS AT A POSITION ABOVE SAID SCRAPING BLADE, SAID CONVEYOR EXTENDING UPWARDLY AND REARWARDLY AND HAVING AN ELONGATED RIGID FRAME MEANS; MEANS FOR PIVOTALLY MOUNTING SAID CONVEYOR FOR MOVEMENT IN A VERTICAL PLANE, SAID MEANS INCLUDING A FORWARDLY AND UPWARDLY EXTENDING CONVEYOR SUPPORT LINK PIVOTED ABOUT A TRANSVERSE AXIS AT ITS UPPER END TO SAID FRAME MEANS INTERMEDIATE THE ENDS OF SAID FRAME MEANS AND ABOUT ANOTHER TRANSVERSE AXIS AT ITS LOWER END TO ONE OF SAID SIDE WALLS; BIASING MEANS YIELDABLY URGING THE LOWER FORWARD END OF SAID CONVEYOR DOWNWARDLY; AND MEANS FOR GUIDING THE LOWER END OF SAID CONVEYOR FROM A FIRST POSITION ABOVE THE LEVEL OF SAID SCRAPING BLADE ASSUMED WHEN NO DIRT IS PASSING OVER SAID BLADE TO AN INTERMEDIATE POSITION FORWARDLY AND DOWNWARDLY OF SID FIRST POSITION ASSUMED WHEN A MODERATE AMOUNT OF DIRT IS PASSING OVER SAID BLADE AND THEN TO A FINAL POSITION FORWARDLY AND UPWARDLY OF SAID INTERMEDIATE POSITION, SAID GUIDE MEANS INCLUDING A RIGID GUIDE ELEMENT DISPOSED ALONG THE INSIDE OF ONE OF SAID SIDE WALLS ADJACENT DISPOSED ALONG THE INSIDE SAID CONVEYOR AND HAVING A GUIDE SURFACE ENGAGED BY SAID CONVEYOR, SAID GUIDE ELEMENT BEING SUPPORTED BY SAID ONE SIDE WALL; AND MEANS FOR PREVENTING UPWARD MOVEMENT OF THE LOWER END OF SAID CONVEYOR BEYOND A PREDETERMINED POINT. 